A conventional electromagnetic valve of this kind is disclosed, for example, in Japanese Laid-open Publication No. 10-299932. This valve includes a first yoke member which has an approximately cylindrical shape, a second yoke member which has an approximately cylindrical shape and which is disposed so as to be opposite to the first yoke member, a bobbin which is molded by resin so as to surround the first yoke member and the second yoke member and which is integral with the first yoke member and the second yoke member, a plunger which is fitted into the first yoke member and the second yoke member so as to be slidable with respect to the bobbin and a valve member which is moved by the plunger.
In the above prior valve, when the first yoke member and the second yoke member are molded with the bobbin by insert molding, at first a molding pin is fitted into inner bores of the first and second yoke members which are opposite each other in the axial direction and the first and second yoke members with the molding pin are put into a cavity of molds. In this condition, a first space between the outer circumferences of the first and second yoke members and an inner surface of the cavity of the mold and a second space between the inner circumferences of the first and second yoke members and an outer circumference of the molding pin are communicated with each other through a circular gap which is formed between an end surface of the first yoke member and an end surface of the second yoke member being opposite to the end surface of the first yoke member. Next, resin is filled in the first space and the first and second yoke members are integral with the bobbin by insert molding. In this condition, the resin is apt to flow out from the first space to the second space through the circular gap and a resin flash is apt to be formed on the inner circumferences of the first and second yoke members. If the resin flash is dropped out during the operation of the electromagnetic valve, the sliding movement of the plunger is disturbed.